Patent GB-809389-A (GB)
Title: Improvements in charge forming and supplying arrangements for internal combustion engines
IPC: F02M1/00
Filed: 1957-01-24
Abstract: 809,389. Carburetters; heating mixture. KOPPENS, L. P. Jan. 24, 1957 [Jan. 31, 1956], No. 2629/57. Classes 7(2) and 7(3) A charge forming and supplying device with means for changing over automatically from one liquid fuel to another in response to the temperature of an element of the device comprises a double float system 3, 3<SP>1</SP> mounted in a single housing such system having in each of the float chambers 2, 2<SP>1</SP>, one of which is for petrol and the other say for kerosene, a valve designed to admit the fuel from the respective float chamber into the further part of the system, such device being not only provided with an idling nozzle a main nozzle a pre-atomizer 15 and a main atomizer, but also with a premixer (Fig. 6) for the preliminary mixing of air and fuel which premixer is situated between the main nozzle and the pre-atomizer, a heat exchanger and evaporator (Fig. 4) in which the mixture of air and fuel which is delivered by the carburetter system 'and which passes out of the main atomizer is heated, evaporated mixed and distributed to the cylinders of the engine, these latter operations being effected in the evaporator partly by making use of the temperature of the exhaust gases from the engine, a change over system actuated by a bimetallic device which opens the valve in one or other of the float chambers in response to the temperature of the evaporator and an electric indicator system which serves to indicate the working of the device and also to operate a pump for volatile fuel, the means for mixing and atomizing the different fuels being interchangeable in such a way that the device is suitable for both light and heavy fuels of different grades and for engines of different sizes. As shown the premixer (Fig. 6) which provides the crude mixture of air and fuel contains a vertical tube 13 the bottom end of which is fitted with the main nozzle. Air is drawn in through a rectangular duct 19. Fig. 5 is a section of the evaporator shown in Fig. 4. From the carburetter 1 the mixture passes through the admission tube 24 to the predistributer 25 whence it makes its way by way of a number of holes into the heating tube 22 in which a partition 29 is situated. The heated mixture passes in the normal manner through tubes 26 into the cylinders. The exhaust gases enter the chamber 23 by way of tubes 27 and leave through the the outlet 28. The wall between chamber 22 and chamber 23 may be formed by mounting two tubes eccentrically with respect to each other so that the wall of air between them is largest on the side where the hot exhaust gases enter chamber 23 and is smallest on the opposite side. The same effect may also be achieved by using an intervening insulating layer of unequal thickness or a tube of unequal wall thickness or a combination of the two. In this way the inner wall of the actual heating chamber 22 will acquire an even temperature. The bimetal controlling device may be fitted at 21 so that the temperature of this part of the evaporator controls the automatic change over from one fuel to another. The premixer together with the two float devices, the idling nozzle, the main nozzle, the preatomizer and the main atomizer are accommodated in a single housing this housing being so thick walled that heat can easily flow from the heat exchanger and evaporator whilst the bottom of the housing and the connecting flange are also of so great a thickness that when this housing is mounted on the heat exchanger and evaporator with a very thin layer of packing in between the heat from this heat exchanger can easily flow into the housing, the result being that this housing and the fuel it contains are brought to the desired temperature. Incorporated in the lid to be placed on top of the housing shown in Fig. 11 is the choke. In the bottom part of the carburetter slightly above the flange 41 is the gas valve.